Inorganic compound for removing polymers in semiconductor processes

ABSTRACT

An inorganic compound for removing polymers after a semiconductor etching process and related methods and apparatus are disclosed. An example compound includes DIW, H 2 SO 4 , H 2 O 2  and HF. An example method for removing polymers generated during etching processes removes the polymers by using the example compound forms a protective oxide film on at least one of a metal line, a via hole and a pad open area by using H 2 O 2 , and protects the at least one the metal line, the via hole and the pad open area by the protective oxide film while removing the polymers by using HF. An apparatus for manufacturing the example compound includes a plurality of tanks in which DIW, H 2 SO 4 , H 2 O 2  and HF are stored, respectively, a main tank for mixing DIW, H 2 SO 4 , H 2 O 2  and HF supplied from the plurality of tanks through supplying tubes connected between the main tank and the plurality of tanks, flow control devices for controlling flow rates of DIW, H 2 SO 4 , H 2 O 2  and HF, through the supplying tubes, and a pump for circulating a mixture of DIW, H 2 SO 4 , H 2 O 2  and HF stored in the main tank.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to semiconductor devices and,more particularly, to an inorganic compound for removing polymers aftera semiconductor etching process.

BACKGROUND

In general, polymers are generated from a photoresist mask, during dryetching processes such as a metal line etching process, a via holeetching process and a pad oxide film etching process. In order to removethe polymers generated during the dry etching processes, amine-basedchemicals and ammonium fluoride-based chemicals have been widely used asa solvent. After removing the polymers with the solvent, the solvent istreated with, e.g., isopropyl alcohol (“IPA”) and methanol andeliminated by a rinsing process using deionized water (“DIW”).

However, such a conventional polymer removing process is complicated,and the equipment needed to perform such a conventional polymer removingprocess is complex because the solvent for removing the polymers shouldbe maintained at a high temperature.

In addition, the solvent is an expensive organic compound and the usedsolvent is typically gathered to be burned up in a separate wastetreatment process, thereby increasing the maintenance costs associatedtherewith. Further, it takes an extended time to complete the rinsingprocess, so that a galvanic corrosion may be caused on semiconductorelements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example apparatus formanufacturing a compound for removing polymers.

DETAILED DESCRIPTION

In one example embodiment, there is provided a compound for removingpolymers generated during etching process, including DIW, H₂SO₄, H₂O₂and HF, which are inorganic chemicals.

In another example, there is provided a method for removing polymersgenerated during etching processes, including removing the polymers byusing an inorganic compound including DIW, H₂SO₄, H₂O₂ and HF, forming aprotective oxide film on a metal line, a via hole or a pad open area byusing H₂O₂, and protecting the metal line, the via hole or the pad openarea by the protective oxide film while removing the polymers by usingHF.

In still another example, there is provided an apparatus formanufacturing a compound for removing polymers generated during etchingprocesses includes tanks in which DIW, H₂SO₄, H₂O₂ and HF are stored,respectively, a main tank for mixing DIW, H₂SO₄, H₂O₂ and HF suppliedfrom the respective tanks through supplying tubes respectively connectedbetween the main tank and the tanks, flow control devices forcontrolling flow rates of DIW, H₂SO₄, H₂O₂ and HF, which arerespectively installed to the supplying tubes, and a pump forcirculating a mixture of DIW, H₂SO₄, H₂O₂ and HF stored in the main tankin order to make the mixture uniform.

As shown in FIG. 1, an example apparatus for manufacturing an inorganiccompound for removing polymers includes a first, a second, a third and afourth tank 100 a, 100 b, 100 c and 100 d in which DIW, H₂SO₄, H₂O₂ andHF are stored, respectively, a main tank 104 for mixing DIW, H₂SO₄, H₂O₂and HF supplied through supplying tubes connected with the first, thesecond, the third and the fourth tank 100 a, 100 b, 100 c and 100 d,respectively, flow control devices 102 a, 102 b, 102 c and 102 dinstalled to the supplying tubes for controlling flow rates of DIW,H₂SO₄, H₂O₂ and HF supplied to the main tank 104, respectively, and apump 106 for circulating the mixture of DIW, H₂SO₄, H₂O₂ and HF to beuniformly mixed.

The compound produced by such an apparatus is used to remove polymersgenerated while a metal line, a via hole, a pad open area and the likeare formed by an etching process using a photoresist as a mask. Further,the compound serves to remove the photoresist residual.

The polymer removing compound may be manufactured using the examplemethod described below.

DIW, H₂SO₄, H₂O₂ and HF are supplied to the main tank 104 by controllingthe respective flow control devices 102 a, 102 b, 102 c and 102 d of therespective supplying tubes connected between each of the first, thesecond, the third and the fourth tank 100 a, 100 b, 100 c and 100 d andthe main tank 104. DIW supplied from the first tank 100 a to the maintank occupies by volume about 70.5% to about 80.5%, preferably 75.5%, ofthe total volume of DIW, H₂SO₄, H₂O₂ and HF being supplied to the maintank 104. At this time, the volume of DIW is controlled by the flowcontrol device 102 a installed to the supplying tube connected betweenthe first tank 100 a and the main tank 104.

H₂SO₄ supplied from the second tank 100 b to the main tank occupies byvolume about 6.5% to about 8.5%, preferably 7.5%, of the total volume ofDIW, H₂SO₄, H₂O₂ and HF being supplied to the main tank 104. At thistime, the volume of H₂SO₄ is controlled by the flow control device 102 binstalled to the supplying tube connected between the second tank 100 band the main tank 104.

H₂O₂ supplied from the third tank 100 c to the main tank occupies byvolume about 15% to about 19%, preferably 17%, of the total volume ofDIW, H₂SO₄, H₂O₂ and HF being supplied to the main tank 104. At thistime, the volume of H₂O₂ is controlled by the flow control device 102 cinstalled to the supplying tube connected between the third tank 100 cand the main tank 104.

HF provided from the fourth tank 100 d to the main tank occupies byvolume about 50 PPM to about 150 PPM. At this time, the volume of HF iscontrolled by the flow control device 102 d installed to the supplyingtube connected between the fourth tank 100 d and the main tank 104.

By such processes, by volume, DIW of about 70.5% to about 80.5%, H₂SO₄of about 6.5% to about 8.5%, H₂O₂ of about 15% to about 19% and HF ofabout 50 PPM to about 150 PPM are stored in the main tank 104. DIW,H₂SO₄, H₂O₂ and HF are circulated by the pump 106 to be uniformly mixed.

The compound produced by such processes can be used to remove polymersgenerated during the etching processes. Further, the compound alsoserves to remove the photoresist residual. In particular, H₂SO₄ and H₂O₂of the compound serve to remove the photoresist residual. H₂O₂ alsoforms a protective oxide film on the metal line, the via hole and thepad open area to protect them from corrosion while HF removes polymers.

The compound for removing polymers is made of the inorganic chemicals,such as DIW, H₂SO₄, H₂O₂ and HF, thereby shortening the time period of arinsing process after the removal of polymers.

In accordance with the example methods described herein, the polymersare removed by using the inorganic compound, thereby shortening the timeperiod of the rinsing process after the removal of polymers andpreventing any galvanic corrosion of the semiconductor elements, e.g.,the metal line, a miss-aligned plug, the pad open area due to theshortened rinsing process time. Further, the compound is made of thecheaper inorganic chemicals, thereby decreasing the maintenance cost.

Although certain methods and apparatus have been described herein, thescope of coverage of this patent is not limited thereto. To thecontrary, this patent covers all embodiments fairly falling within thescope of the appended claims either literally or under the doctrine ofequivalents.

1. A method for removing polymers generated during an etching process,comprising the steps of: removing the polymers from a metal line, a viahole, or a pad open area by using an inorganic compound including DIW,H₂SO₄, H₂O₂ and HF; forming a protective oxide film on the metal line,the via hole or the pad open area by using H₂O₂; and protecting themetal line, the via hole or the pad open area by the protective oxidefilm while removing the polymers by using HF, wherein DIW occupies byvolume about 70.5% to about 80.5% of the total volume of DIW, H₂SO₄H₂O₂and HF, H₂SO₄ occupies by volume about 6.5% to about 8.5% of the totalvolume of DIW, H₂SO₄, H₂O₂ and HF, H₂O₂ occupies by volume about 15% toabout 19% of the total volume of DIW, H₂SO₄, H₂O₂ and HF, and HFoccupies by volume a range of greater than 100 PPM and approximatelyless than or equal to 150 PPM of the total volume of DIW, H₂SO₄, H₂O₂and HF, and wherein the total volume % of DIW, H₂SO₄, H₂O₂ and HF isabout 100%.
 2. The method of claim 1, wherein DIW occupies by volumeabout 75.5% of the total volume of DIW, H₂SO₄, H₂O₂ and HF.
 3. Themethod of claim 1, wherein H₂SO₄ occupies by volume about 7.5% of thetotal volume of DIW, H₂SO₄ H₂O₂and HF.
 4. The method of claim 1, whereinH₂O₂ occupies by volume about 17% of the total volume of DIW, H₂SO₄,H₂O₂and HF.
 5. The method of claim 1, further comprising storing theDIW, the H₂SO₄, the H₂O₂ and the HF in separate tanks prior toapplication to the semiconductor device feature.
 6. The method of claim5, further comprising mixing the DIW, the H₂SO₄, the H₂O₂ and the HF ina common tank to form the inorganic compound prior to application to thesemiconductor device feature.
 7. The method of claim 6, furthercomprising delivering the DIW, the H₂SO₄, the H₂O₂ and the HF to thecommon tank from the separate tanks via supplying tubes.
 8. The methodof claim 7, wherein the supplying tubes comprise flow control devicesthat regulate the flow of the DIW, the H₂SO₄, the H₂O₂ and the HF intothe common tank.
 9. The method of claim 8, wherein the flow controldevices deliver the DIW, the H₂SO₄, the H₂O₂ and the HF at individuallyvaried rates.
 10. The method of claim 9, wherein the common tankcomprises a pump that circulates and uniformly mixes the the DIW, theH₂SO₄, the H₂O₂ and the HF in the common tank.
 11. The method of claim1, further comprising forming the metal line, the via hole, or the padopen area by an etching process using a photoresist as a mask.
 12. Themethod of claim 11, wherein the polymers comprise residual photoresistmaterial.